1. Field of the Invention
The present invention relates to a method to produce an optical module that installs a distributed feedback laser diode (hereafter denoted as DFB-LD), in particular, the optical module produced by the present method is utilized for the optical transmission of an analog data.
2. Related Prior Art
The United States patent, the U.S. Pat. No. 5,802,096, has disclosed a method to manufacture an optical module for the analog data transmission. The method disclosed therein inspects the composite second order beat (hereafter denoted as CSO) of the DFB-LD after a laser chip is installed within the module package.
In the DFB-LD, in particular, that is applied in the analog transmission, the CSO performance thereof influences the transmission system. The CSO performance of the DFB-LD strongly depends on the inner structure of the DFB-LD device. Accordingly, in a case where the CSO performance is inspected after the DFB-LD device is installed within the module housing, the yield becomes hard to be kept in an acceptable level.